Spack GitLab CI Pipeline - Environment yaml does not have "gitlab-ci" section

Question

Using example files .gitlab-ci.yml and spack.yaml as in https://spack.readthedocs.io/en/latest/pipelines.html , with this change,

  script:
    - spack env create ENV
    - spack env activate --without-view ENV

and docker tags commented out, yet on running .gitlab-ci.yml,

 Error: Environment yaml does not have "gitlab-ci" section

Had already tried in spack.yaml to rename section ci: with gitlab-ci: though with same erring outcome.

Thus asking for orientation as to how to start solving this.

---

Contents of .gitlab-ci.yml as follows,

stages: [generate, build]

variables:
  SPACK_REPO: https://github.com/scottwittenburg/spack.git
  SPACK_REF: pipelines-reproducible-builds

generate-pipeline:
  stage: generate
  tags:
    # - docker
  image:
    name: ghcr.io/scottwittenburg/ecpe4s-ubuntu18.04-runner-x86_64:2020-09-01
    entrypoint: [""]
  before_script:
    - git clone ${SPACK_REPO}
    - pushd spack && git checkout ${SPACK_REF} && popd
    - . "./spack/share/spack/setup-env.sh"
  script:
    - spack env create ENV
    - spack env activate --without-view ENV
    - spack -d ci generate
      --artifacts-root "${CI_PROJECT_DIR}/jobs_scratch_dir"
      --output-file "${CI_PROJECT_DIR}/jobs_scratch_dir/pipeline.yml"
  artifacts:
    paths:
      - "${CI_PROJECT_DIR}/jobs_scratch_dir"

build-jobs:
  stage: build
  trigger:
    include:
      - artifact: "jobs_scratch_dir/pipeline.yml"
        job: generate-pipeline
    strategy: depend

as well as spack.yaml,

spack:
  view: false
  concretizer:
    unify: false

  definitions:
  - pkgs:
    - zlib
    - bzip2
  - arch:
    - '%gcc@7.5.0 arch=linux-ubuntu18.04-x86_64'

  specs:
  - matrix:
    - - $pkgs
    - - $arch

  mirrors: { "mirror": "s3://spack-public/mirror" }

  ci:
    enable-artifacts-buildcache: True
    rebuild-index: False
    pipeline-gen:
    - any-job:
        before_script:
          - git clone ${SPACK_REPO}
          - pushd spack && git checkout ${SPACK_CHECKOUT_VERSION} && popd
          - . "./spack/share/spack/setup-env.sh"
    - build-job:
        # tags: [docker]
        image:
          name: ghcr.io/scottwittenburg/ecpe4s-ubuntu18.04-runner-x86_64:2020-09-01
          entrypoint: [""]